Panel fastener

ABSTRACT

A screw-type fastener comprising two cooperable assemblages for releasably securing a panel having one of said assemblages to an underlying support structure such as a sub-panel or other framework having the other assemblage. The said other assemblage of the fastener comprises a tubular housing enclosing a screw member which projects forwardly to an open end of the housing, toward the opening thereof. The said one fastener assemblage comprises a floating stud body carried by the panel and having an internally threaded bore which is adapted to receive the screw member when the stud body is applied thereto. The housing has ratchet rings encircling the screw member, provided with opposed faces containing sloped radial teeth which engage one another. One ring is keyed to rotate with the stud body, and the other is keyed for longitudinal non-rotary movement in the housing. A spring in the housing maintains the rings in contact. The screw member is mounted for floating, turning movement in the housing, and is yieldably restrained by a unidirectional or non-reversing rotary detent as the stud body advances on the screw until a predetermined torque is reached. Thereafter the detent yields in the manner of a one-way ratchet or overload clutch to enable the screw member to turn with the stud body when the fastener is completely pulled up, thereby preventing overtightening. The limiting of the torque eliminates personnel-related error or misjudgements. Reverse turning of the stud body unscrews it from the screw member in a positive manner due to the one-way or non-reversing action of the detent.

CROSS REFERENCES TO RELATED APPLICATIONS

Copending application of Joseph R. Metz U.S. Ser. No. 612,268 filed May21, 1984, entitled PANEL FASTENER and having common ownership with thepresent application.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY-SPONSOREDRESEARCH AND DEVELOPMENT

Research and development of the present invention and application havenot been Federally-sponsored, and no rights are given under any Federalprogram.

BACKGROUND OF THE INVENTION Field of the Invention

This invention relates generally to panel fastener devices of the typewhich are employed to secure, in a removable manner, a top panel to anunderlying panel or support structure, and more particularly to devicesof this type which incorporate a screw that is exposed at an accessopening in the support structure and adapted to be engaged by aninternally threaded fastener stud held captive in a correspondingopening of the panel.

DESCRIPTION OF THE RELATED ART INCLUDING INFORMATION DISCLOSED UNDER 37CFR §§1.97-1.99

The invention relates more particularly to improvements in the panelfasteners illustrated and described in the copending application aboveidentified, and in U.S. Pat. No. 3,294,140 dated Dec. 27, 1966 andissued to F. J. Cosenza.

The patented device shows a fastener of the type indicated above,comprising a housing mounted on a sub-structure or subpanel, in whichhousing there is rigidly carried a screw having a threaded part thatprojects toward an access opening in the sub-structure. The patentedfastener further comprises a cooperable part in the form of a studhaving an internally threaded bore, which stud is captive on anoverlying panel and can be inserted into the access opening of thesub-panel so as to engage the threads of the screw therein, thereby topull the overlying panel toward the sub-panel or supporting structure.The stud is held captive on the overlying panel by means of a retainerring having inwardly projecting lugs which are seated in longitudinalgrooves in the exterior surface of the stud. The screw is held captivein its housing and is fixed against rotation by means of lugs or tabs53, as described in column 5, lines 50-53 of the patent. There are tworatchet rings which function to provide a detent action that minimizesthe possibility of the stud inadvertently becoming unscrewed undersevere operating conditions such as excessive vibration. The ratchetrings are maintained in engagement with one another by a coil springthat bears against the underside of the head of the screw.

While the above construction operated in a generally satisfactory manneras far as withstanding vibration and high temperatures, there existed adistinct drawback in that the studs were susceptible of overtighteningby the installer. Also, problems arose with the improper "starting" ofthe threads during initial engagement of the stud and screw. Under suchcircumstances, damage to either the stud or screw could occur, renderingthe entire assembly inoperative and necessitating replacement of theinoperative parts. Since panels of this type are frequently employed inaircraft, guided missiles, etc., where field maintenance is necessary,such replacements caused considerable problems. In addition, in thepatented device the screw was rigidly held in position in the housing.Where there existed slight misalignments resulting from eithermanufacturing tolerances or perhaps warping of the panel or theunderlying support structure, there could occur difficulty in properly"starting" the threads, if the fastener stud carried by the overlyingpanel did not properly align with the respective screw. Since noprovision was made for enabling the screw to yield or shift position inthe housing, even slightly, there was a possibility of binding orseizing of the parts. The above drawbacks in the patent constitutedserious objections where screw-type fasteners were employed.

In the copending application above identified the disadvantages of thepatented device are overcome. However, with the construction shown inthe application the possibility still existed that difficulty could beexperienced in the unscrewing of the fastener, if any binding orfriction of the threads proved to be greater than the detent restraintof the means which prevented overtightening of the screw. In someinstances, such as when appreciable rust or dirt formed on the threads,the threaded parts would not unscrew and separate easily.

SUMMARY OF THE INVENTION

The above disadvantages and drawbacks of prior panel fasteners andparticularly the drawback of the fastener in the identified copendingapplication are obviated by the present invention which has for anobject the provision of an improved panel fastener which while still ofsimple construction is especially reliable in use and positivelyreleasable or separable as to its parts, even after use over extendedperiods of time.

Another object of the invention is to provide an improvedpositive-release panel fastener as above set forth, wherein during eachsubsequent installation, the allowable torque is reliably automaticallylimited whereby there is eliminated the possibility of overtightening ofthe fastener stud and stripping or damaging of the screw threads oneither the screw member or stud.

A further object of the invention is to provide an improvedpositive-release panel fastener as above characterized, wherein releaseof the fastener parts is quickly had regardless of any operator-relatederror, since no judgement is required on the part of the person removingthe panel. The maximum torque which can be applied to the fastener isavailable to unscrew the parts, without diminution or adverse influencefrom other functions.

Still another object of the invention is to provide an improvedpositive-release panel fastener of the kind indicated, whereinaccommodation is made for slight misalignments between the screw andfastener stud without upsetting the positive release action. Suchmisalignments typically occur as a result of manufacturing tolerances,or warping of one or more of the parts. When it is realized that atleast four or more of such fasteners are usually employed with aparticular panel, the likelihood of all of the bored and threaded studsaligning exactly with their corresponding screws is remote, at best.Such a circumstance might occur in certain instances, but it wouldprobably result more from chance than from deliberate design andmaintenance procedures that of necessity involve specific tolerances andfreedom from warping, stresses, or other dimensional changes resultingfrom temperature fluctuations, etc.

Yet another object of the invention is to provide an improvedpositive-release panel fastener as outlined above, wherein thepossibility of damage occurring to the fastener, particularly thepositive-release and threaded parts thereof, is virtually eliminated,thereby greatly increasing the reliability and extending the useful lifeof the device.

A still further object of the invention is to provide an improvedpositive-release fastener as above set forth, which is especiallyresistant to malfunction from extreme operating conditions liketemperature fluctuations, vibration, moisture, etc., thus making thedevice especially well suited for use in harsh environments such aswhere aircraft of one form or another are involved. It can be readilyappreciated that a positive release, and reliable performance and longlife are extremely important in vital installations, and that steps toavoid failure of equipment are undertaken wherever possible.

The above objects are accomplished by the provision of an improved panelfastener of the type which releasably secures an overlying panel to anunderlying or support structure having an access opening, such improvedfastener comprising a housing having a tubular bore in which there isdisposed a screw member, means for securing the housing at the accessopening of the underlying support structure, and an internally threaded,hollow fastener stud which is captive in an opening in the overlyingpanel, such opening being alignable with the access opening of thesupport structure. During initial installation, yieldable detent meansin the housing engage the stud, offering nominal resistance against freeturning and thus minimizing the possibility of subsequent loosening dueto vibration. The screw member is mounted in the housing for turningmovement, and a yieldable one-way action detent, separate and distinctfrom the above-mentioned detent means, is carried by the housing andnormally impedes in one direction any turning of the screw member exceptunder conditions where it experiences excessive torque, such as wouldresult from overtightening of the fastener stud or possible improper"starting" of the threads of the screw member and those of the stud. Theuseful intended maximum applied driving torque to be experienced by thecaptive stud is set at a desired, predetermined figure, and if suchfigure is exceeded it will result in a yielding and restrained turningof the screw member that cooperates with the stud. Operator-relatederror is thereby eliminated from the installation procedure. Theyieldable detent positively prevents relative turning in the opposite orreleasing direction of the screw member, whereby a positive release ofthe fastener is assured at all times regardless of any rusting or dirtconditions. This is effective all without sacrificing simplicity orreliability in construction. Significantly extended life and positiverelease are thus had, and maintenance requirements are accordinglyreduced.

Other features and advantages will hereinafter appear.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, illustrating several embodiments of the invention:

FIG. 1 is an axial sectional view of the improved panel fastenerconstruction of the present invention, illustrating the underlyingsupport structure and panel overlay associated therewith. One part ofthe fastener comprises a housing which is carried behind an access holein the support structure, and a second part comprises a fastener studwhich is held captive in a hole in the panel to be attached and which isintended to remain with said panel at all times. FIG. 1 is taken on theline 1--1 of FIG. 2.

FIG. 2 is a rear elevation of the housing part of the panel fastenerconstruction of FIG. 1.

FIG. 3 is a side elevation of the screw member employed in the panelfastener of the invention.

FIG. 4 is a left end elevation of the screw member of FIG. 3.

FIG. 5 is a rear elevation of the mounting or clamping sleeve of thefastener construction, by which the fastener housing is secured to theunderlying structure.

FIG. 6 is a bottom plan view of the sleeve of FIG. 5.

FIG. 7 is a right end elevation of the sleeve of FIGS. 5 and 6.

FIG. 8 is a side elevation of a detent plate or disk carried in thehousing and which is adapted to engage the head of the screw member inFIG. 1.

FIG. 9 is a rear elevation of the detent plate of FIG. 8.

FIG. 10 is a rear elevation of a rear cover plate which forms the closedrear end of the housing of the fastener construction.

FIG. 11 is a side elevation of the cover plate of FIG. 10.

FIG. 12 a front elevation of one of two ratchet rings carried in thehousing of the fastener construction of FIG. 1.

FIG. 13 is a side elevation of the ratchet ring of FIG. 12.

FIG. 14 is a rear elevation of a second ratchet ring carried in thehousing of the fastener construction of FIG. 1.

FIG. 15 is a side elevation of the ratchet ring of FIG. 14.

FIG. 16 is rear elevation of the front cover plate for the housing ofthe fastener construction of FIG. 1.

FIG. 17 is a side elevation of the cover plate of FIG. 16.

FIG. 18 is rear elevation of the tubular housing per se, of FIG. 1.

FIG. 19 is a section taken on line 19--19 of FIG. 18.

FIG. 20 is a side elevation of one type of fastener stud which can beemployed with the fastener construction of FIG. 1, this constructionconstituting another embodiment of the invention.

FIG. 21 is a front elevation of the stud of FIG. 20.

FIG. 22 is a side elevation of the stud employed in the fastenerconstruction of FIG. 1.

FIG. 23 is a front elevation of the stud of FIG. 22.

FIG. 24 is a rear elevation of a modified housing having a flutedinterior surface, this constituting another embodiment of the invention.

FIG. 25 is a section taken on the line 25--25 of FIG. 24.

FIG. 26 is a top plan view of a retainer ring employed to hold captivethe stud of FIG. 1 in an overlying panel.

FIG. 27 is a section taken on the line 27--27 of FIG. 26.

FIG. 28 is a front elevation of a modified housing construction for apanel fastener, wherein the housing can float a limited extent withrespect to its mounting sleeve, and thus with respect to the underlyingsupport surface, thereby to compensate for slight misalignments betweenthe fastener studs carried on an overlying panel and the respectivehousings.

FIG. 29 is a side elevation of the housing construction of FIG. 28.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring first to FIG. 1 there is illustrated in dotted outline asupport structure generally designated 10, having an access opening 12behind which there is mounted one part 14 of the present improved panelfastener device. The fastener part 14 is adapted to receive a threadedstud 16 of a cooperable fastener part, such stud being captive in a holein an outer or overlying panel 18. The stud 16 when turned enables thepanel 18 to be secured to the support structure 10 with a minimum oftime and effort. The stud 16 in FIG. 1 is shown as occupying theaperture or opening 20 of the panel 18, such aperture having a conicalportion 22 and a cylindrical portion 24. On the underside of the panel18 there is a generally flat recess or counterbore 26 which is adaptedto receive a retainer ring 28 to be described below.

Carried at the rear of the support structure 10 is a generallycylindrical housing 30 having a longitudinal bore 32, the front of thehousing having a mounting plate 34 that is preferably welded to thehousing. The plate 34 has an opening 36 in line with the access opening12 of the support structure 10. The plate 34 is held by a sheet metalclamping member or sleeve 38, shown also in FIGS. 5-7, having twooppositely-disposed mounting holes 40 that align with correspondingholes in the support structure 10 to enable the clamping member 38 to besecured by suitable screws or rivets, etc., not shown. The clampingmember 38 has four retainer ears 42 which are bent radially inwardlyover the mounting plate 34 so as to secure the latter at the rear of thesupport structure 10 as shown in FIG. 1; preferably, the ears aresomewhat loose fitting, and enable a limited side-to-side movement ofthe housing 30 and plate 34 for purposes of self-alignment.

Disposed mostly within the housing 30 is a screw member 44 having a headportion 46 and a threaded shank portion 48, the latter projectingforwardly just past the central opening in the clamping member 38. Theundersurface 50 of the head of the screw member 44 engages a thrustwasher 51 positioned by an internal annular shoulder 52 in the bore 32of the housing 30 as shown.

Also, a pair of springs 54, 56 is provided, each being of differentpitch from the other and having different diameters. The springs 54, 56surround the threaded shank portion 48 of the screw member 44 as shown.The ends of the springs 54, 56 bear against the thrust washer 51 at thescrew head 46 on the one hand, and against one of two ratchet rings onthe other hand; the first ring is designated 58, and the second 60. Thering 58 is illustrated particularly in FIGS. 12 and 13, and the ring 60in FIGS. 14 and 15. One face of the ring 58 hascircumferentially-arranged radial sloped teeth 62 which are adapted tomate with corresponding radial sloped teeth 64 on the ring 60 when thetwo parts are superposed as in FIG. 1, the force of the springs 54, 56biasing the rings into engagement with one another. The ring 58 hasoppositely-disposed lugs 66, 68, which together with groove formations70, 72 in the longitudinal bore 32 of the housing 30 constitute a keyingmeans that permits relative sliding movement of the ring 58 along partof the length of the bore 32 but prevents relative rotation between thering and housing 30. The lugs 66, 68 and the groove formations areclearly shown in FIG. 1. The remaining ring 60 also has two projectionsor lugs 74, 76 extending in an axial direction from that face which doesnot contain the teeth 64. These lugs are intended to be received incorresponding grooves or slots 78, 80 (FIG. 22) in the end of the stud16 when the latter is positioned at the opening 12.

Referring again to FIG. 1, the stud 16 has a threaded bore 82 which canreceive the threaded shank portion 48 of the screw member 44 when thestud is positioned over the access opening 12. The opposite, outer endof the stud 16 has a key formation, in this case an hexagonal recess 83,FIG. 23, for receiving a suitable tool in order to effect tightening ofthe stud on the screw member 44.

In accordance with the present invention, unique means are provided tomount the screw member 44 in the housing 30, including a yieldabledetent or slip clutch for positively preventing relative turningmovement of the screw member 44 in one direction with respect to thehousing 30, and for yieldably restraining relative turning movement inthe opposite direction. With regard to the yieldable restraint of thescrew member, the latter will not turn when there is applied to it atorque less than a predetermined given figure, whereas it will turn whenthere is applied to it a torque in excess of the said predetermined,given figure. In addition, the mounting means permits a degree oflooseness or play between the walls of the housing bore 32 and the head46 of the screw member 44, to minimize the possibility of binding orjamming, which might result from slight misalignments between the screwmember, housing and stud.

As part of such mounting, there is disposed between the undersurface 50of the head 46 of the screw member 44 and the annular shoulder 52 in thehousing, the thrust washer 51 mentioned above, constituting a thrustbearing.

The unique mounting provided by the present invention for the screwmember 44 is in effect a positive one-way clutch or detent connectedbetween the screw member and the housing 30, which permits it to haverelative turning in one direction only if forcibly driven in suchdirection but positively prevents relative turning in the otherdirection regardless of the turning force applied.

To accomplish this, as illustrated in FIGS. 3 and 4, the outer or rearsurface of the head 46 of the screw member 44 is provided with sixuni-directional-acting cam teeth 90 which extend in radial directions,these being adapted to coact with six similar corresponding cam teeth 92on a base or anchorage plate 94 particularly illustrated in FIGS. 8 and9. The plate 94 is rigidly carried on a flatted hub 96 which is receivedin keying relation in a similarly shaped opening 98 in a rear end plate100 of the housing 30. The plate 100 constitutes the closure for therear of the housing, and is held in position by an inturned rear edgethereof, curled inward as shown after the various parts are inserted inthe housing from the rear. The end plate 100 is illustrated in FIGS. 10and 11, and has oppositely disposed lugs 102, 104 which are received incorresponding slots or grooves 106, 108 in the housing, FIG. 2.

As illustrated, the base plate 94 is not rigid with respect to eitherthe end plate 100 or the housing 30, but instead there is disposedbetween the plate 100 and base plate 94 a pair of Belleville washers110, 112. The central portions of the washers are preferably juxtaposed,with their peripheries being spaced apart, in order to provide thedesired spring biasing action to the base plate 94. As can be readilyunderstood, the plate 94 and its hub 96 can undergo limited movementaxially of the housing 30, from the position shown in FIG. 1, toward theleft, by a slight extent.

With such arrangement the screw member 44 can under specialcircumstances be forcibly turned but with restraint, clockwise as viewedfrom its right or small end. The restraint is provided by thecooperative cam teeth 90, 92 which click or cam past each other as theirsloping sides engage and the washers 110, 112 yield. However, the screwmember 44 is positively prevented from turning in the opposite orcounterclockwise direction as viewed from the right, due to thenon-sloping sides of the cam teeth 90, 92 becoming engaged with eachother.

Such one-way positive restraint insures that, when the panel 18 is to beseparated from the supporting structure 10 this can be accomplishedwithout difficulty because a positive drive is had in effect as the stud16 is turned in unscrewing direction due to the screw member 44 beingpositively held against counterclockwise turning. Thus, suchcircumstances as rusting or abrasion of the threads or the lodging ofdirt thereon will not defeat the unscrewing of the fastener, which wasnot the case in the device of my prior application identified above.

The present fastener has a retainer ring 28 associated with the stud 16,for holding the latter captive in the panel 18 when it is not installedon the support surface. The ring 28 is shown in FIGS. 1, 26 and 27, andis seen to comprise a first cup shaped member 114 preferably constitutedas a simple metal stamping, a second cup shaped member 118, and a spring120 having a distorted or serpentine-like circular configuration, beingcharacterized by wavelike undulations. The inner peripheral portions ofthe undulations define a first, relatively small diameter circle, andthe outer peripheral portions define a second, larger circle. Thedimensions are such that the spring has the configuration shown when notinstalled on the stud 16. The spring is seen to extend circumferentiallythrough almost 360 degrees, with its opposite ends being juxtaposed. Theends of the spring are adjacent the outer periphery thereof. Alignedopenings 122 and 124 in the cups 118 and 114 respectively are generallycircular, and have roughly the same diameter, this being between that ofthe first and second circles mentioned above. The diameter of theopenings 122 and 124 is sufficient to enable the ring 28 to be passedover the inner end of the stud 16 and slid over the cylindrical partthereof.

As shown in FIG. 22, the stud 16 has a conical portion 126 constitutingone wall of a groove 128, and a second annular wall in the form of ashoulder 130, constituting the opposite groove wall. A lead-in formation132 of conical configuration facilitates initial installation of theretainer ring 28 on the stud after the latter is inserted into the hole20 in the panel 18. The dimensions of the annular shoulder 130 andspring 120 are such that the ring 28 can slide from the positionillustrated in FIG. 1, to a position wherein the spring occupies thegroove 128 when the panel 18 is free; however, the spring preventscomplete release of the stud therefrom, thus eliminating the possibilityof the stud becoming lost. The area adjacent to the conical head of thestud is frequently employed by maintenance personnel as a handle forcarrying the panel about, or to facilitate positioning of the panel asrequired during installation. The retainer ring 28 has been found to besufficiently rugged to prevent inadvertent separation of the stud andpanel in the course of rough handling of this type.

The operation of the improved fastener construction of the presentinvention can now be readily understood by referring to FIG. 1. Thehousing 30 is permanently retained on the structure 10 at the rear ofthe access opening 12. The panel 18 can be installed and removed fromthe support structure 10, with the stud 16 being retained captive in thehole 20 of the panel 18 when the latter is removed. Although FIG. 1shows but a single fastener, it will be understood that typically anumber of similar fasteners are employed about the periphery of thepanel 18, in order to provide multiple points of attachment to theunderstructure or support surface.

When it is desired to install the panel, the stud 16 is positioned overthe appropriate access opening 12 such that the stud bore 82 aligns withthe threaded shank portion 48 of the screw member 44. With a suitabletool engaging the outer keying configuration of the stud 16, such as anAllen wrench or spline, etc., the stud is rotated slowly clockwise untilthe internal threads thereof become engaged with the external threadedshank portion 48 of the screw member 44. As this is occurring, the lugs74 and 76 of the ring 60 will be received in the slots 78, 80 of thestud 16, FIGS. 15 and 22, and the ratchet ring 60 will begin to turnwith the stud. Since the ratchet ring 58 is keyed against rotation, therelative turning between the two rings will cause a clicking or by-passof the teeth 62 and 64 against the action of the springs 54, 56. Thedetent effect of the ratchet rings and the springs is such that forevery few degrees of turning there must be overcome the force of thesprings in order to allow the teeth to by-pass; accordingly, resistanceis encountered as the stud is threaded onto the screw member. Inaddition, however, resistance would also be encountered if the stud wereunscrewed, and there is thus prevented inadvertent loosening of the stud16 from the screw member 44 after installation, such as might otherwiseoccur under vibration.

As the stud 16 approaches its fully on position, the force of thesprings 54 and 56 increases, and the torque required to either tightenor loosen the stud accordingly increases, this being the desired effect,since the maximum resistance to inadvertent loosening is needed when thestud is fully seated.

With prior devices of this type the proper amount of torque to beapplied has involved substantial judgement on the part of the installer.In many cases, excessive torque has been applied, resulting fromcarelessness or lack of attention by such personnel.

By the present invention, the application of a clockwise torque to thestud 16 which exceeds a predetermined, given figure automaticallyrenders operative the yieldable detent 46, 94, 110, 112 and theapplication of a sufficiently large counterclockwise torque positivelyresults in an unscrewing of the stud 16 from the screw member 44. Forthe clockwise torque, the screw member 44 normally ultimately begins torotate clockwise with the stud 16 after complete pull-up. During suchultimate rotation, the base plate 94 is periodically forced axiallytoward the left in FIG. 1, as the cam teeth 90 and 92 click past oneanother. The Belleville washers 110, 112 yield as this occurs. As aresult, no reliance is placed on operator judgement, since the operatingtorque is automatically limited; overtightening and stripping of thethreads of either the stud 16 or the screw member 44 thus cannot occur.

For the counterclockwise torque, the screw member 44 is positively heldagainst counterclockwise rotation in the housing 30 by the cam teeth 90,92 and anchor or base plate 94. Release of the panel 18 is thus assuredat all times.

It is noted that there can exist a slight clearance space between thehub 96 for the anchor plate and the hole 98 in the end plate 100.Clearance space here minimizes possible problems with binding of theparts during the axial movement of the hub. Also, it allows for slightvariances in the position of the head 46 of the screw member 44 withinthe housing. The Belleville washers tend to seat the base plate 94properly in the absence of such variances, but at the same time permit alimited selfalignment to occur between the various parts of the device.

Additional clearance spaces can also exist between the head 46 of thescrew member 44 and the housing bore 32, the outer periphery of thethrust washer 51 and the bore 32, the hole in the thrust washer 51 andthe unthreaded portion of the screw member 44, and the outer peripheriesof both ratchet rings 58 and 60 and the housing bore. These spacespermit smooth operation of the device, and thereby minimize thepossibility of binding or jamming of the various moving parts. Freedomfrom malfunction and/or failure is considered extremely important in thepresent device, since panel fasteners of this general type are oftenemployed in aircraft, and maintenance is frequently done in the field.Jamming of a part or stripping of a thread would pose substantialproblems under such circumstances.

A modified form of stud is shown in FIG. 20, designated 16a. Theconstruction is essentially like that of the first mentioned stud 16,with the exception of a different configuration for the head. Whereasthe stud 16 was intended to be fully recessed in a countersunk hole inthe panel 18, the stud 16a could be employed with other types of panels,where a flush surface configuration was not important. Again, the studhead is provided with a keying aperture 83a, for engagement by asuitable tool.

Another embodiment of the invention is shown in FIGS. 24 and 25, whichdepict a modified housing 30a that could be substituted for the housing30 shown in FIGS. 1, 18 and 19. In place of the diametrically opposedlongitudinal grooves 70 and 72 illustrated in FIGS. 1, 18 and 19, thebore of the housing 30a is provided with a fluted configuration 133 inthe area where sliding movement of the ratchet rings 58 and 60 occurs.In this particular construction, the ratchet ring 58 of FIGS. 1, 12 and13 could be modified slightly by merely rounding out the lugs 66, 68thereof, such that they would occupy any pair of opposite grooves of thefluted bore 133 of the housing 30a. The ratchet ring 58 could thus slideaxially of the housing, but would be restrained against turning withrespect thereto. The ring 60 would rotate simultaneously with the stud,as in the previous construction.

While this construction has been found to be somewhat more expensive toproduce than that of the previous figures, it has the advantage thatinitial positioning of the ratchet ring 58 would be simplified, since itcould be installed in any one of a number of angular positions withrespect to the housing as a result of the symmetry of the bore.

Still another modification of the fastener is illustrated in FIGS. 28and 29, wherein the housing designated 30b is secured in floatingrelation to a modified sheet metal clamping member or sleeve 38b havingfour ears 42b which are disposed at roughly 45° with respect to thevertical axis of the member. By suitable formation of the ears 42b, adegree of lateral shifting of the housing 30b is made possible withrespect to the member 38b, this being desirable in certain installationsinvolving alignment of multiple fastener studs and multiple fastenerhousings. Misalignments sometimes result from bending or warping of themetal parts when they are subjected to stress, in combination withexposure to multiple heat/cooling cycles, or other harsh environmentalfactors which can cause permanent changes in the physical dimensions ofsuch parts. In other respects the arrangement of FIGS. 28 and 29 issimilar to that already discussed in connection with FIG. 1.

It is to be noted that with the present construction, not only isovertightening circumvented but also a positive loosening is alwaysassured in addition to eliminating the possibility of forcing a studonto a screw thread where the threads have not been "started" correctly.With respect to this latter, if the threads do not engage correctly atthe onset of installation, rather than a possible stripping occurring,the yieldable detent located at the screw head will come into play, andthere will be an immediate indication to the installer that a problemwith this particular unit exists. It will thus be possible for theinstaller to positively back off on the stud, and "re-start" thethreads.

As can be readily understood, the housing essentially completelyencloses and conceals the yieldable detent. This has the advantage ofkeeping dirt or debris out of the area, as well as discouragingtampering. Also, it is unlikely that the parts would be inadvertentlydamaged from bumping, jarring, etc. These are considered to be importantadvantages of the present invention.

From the above it can be seen that I have provided novel and improvedfastener constructions which are both simple in their structure while atthe same time being both rugged and reliable under relatively harshconditions, such as vibration, and being capable of satisfactoryoperation over extended periods. By virtue of the one-directional torquelimit feature being incorporated directly in the fastener housing, thereis always a positive release insured for the fastener, with nopossibility of damage during installation due to error on the part ofmaintenance personnel, regardless of whether they are employing manualtools or power operated drivers. Accordingly the chances of amalfunction or failure are greatly reduced as compared to operationsinvolving the prior art devices.

The present fastener constructions thus constitute a distinct advanceand improvement in this field.

Each and every one of the appended claims defines an aspect of theinvention which is separate and distinct from all others, andaccordingly each claim is to be treated in this manner when examined inthe light of the prior art devices, in any determination of novelty orvalidity.

Variations and modifications are possible without departing from thespirit of the claims.

I claim:
 1. A fastener for releasably securing a panel to an underlyingsupporting structure having an access opening, comprising incombination:(a) a tubular housing having a longitudinal bore, (b) meansfor securing said housing to the supporting structure, with the bore ofthe housing located at the access opening thereof, (c) a screw membercarried in the housing bore, having a threaded portion extending towardan open end thereof and accessible from said access opening, said screwmember having a head disposed in said housing, (d) the panel having anopening adapted to be located at the access opening in the supportingstructure, (e) a stud having a bore with internal threads adapted tomate with the threaded portion of the screw member when the panel isplaced over the supporting structure with its opening adjacent saidaccess opening and the stud engaged with and turned with respect to thescrew member, (f) a detent device in said housing for engagement by thestud to prevent inadvertent rotation thereof with respect to the housingand consequent loosening thereof on the screw member under conditions ofvibration, (g) means providing a movable mounting for the screw memberin the housing to enable turning movement, and (h) a yieldableuni-directional detent means carried by the housing and continuallyengaging the head of the screw member so as to normally prevent itsturning in one direction during application of the stud to the threadedportion of the screw member except under conditions of excessive torque,thereby reducing the likelihood of damage occurring to the screw memberor stud from possible overtightening, (i) said uni-directional detentmeans at all times positively preventing turning of the screw member inthe opposite direction so as to insure removal of the stud therefromwhen the latter is turned in unscrewing direction.
 2. A fastener asdefined in claim 1, wherein:(a) said means providing a movable mountingfor the screw member comprises an annular shoulder in the bore of thehousing, (b) a washer engaging said shoulder, (c) said washer beingdisposed between shoulder and the head of the screw member, andconstituting a thrust bearing for enabling turning of the screw memberto occur.
 3. A fastener as defined in claim 1, wherein:(a) saidyieldable detent means comprises means defining a plurality of cam teethon the head of the screw member, (b) a plate disposed in the housingadjacent the screw member head, (c) said plate having a plurality of camteeth about its periphery adapted to cooperate with the cam teeth on thescrew member head to permit relative turning movement in one directionand prevent relative turning movement in the other direction, (d) meansconnected with the plate, keying the latter to the housing, and (e)spring means biasing the plate into engagement with the head of thescrew member such that the cam teeth on the latter are normally biasedto forcibly engage the cam teeth on the plate, and the screw member isthereby normally retained against turning in one direction with respectto the stud except under said conditions of excessive torque.
 4. Afastener as defined in claim 3, wherein:(a) said housing is closed atone end, (b) said spring means comprising a Belleville washer disposedbetween the said closed end of the housing and the plate.
 5. A fasteneras defined in claim 3, wherein:(a) said housing is closed at one end,(b) said spring means comprising a pair of Belleville washers disposedbetween the said closed end of the housing and the plate, (c) saidwashers having their centers juxtaposed and their peripheries in spacedrelation with respect to one another.
 6. A fastener as defined in claim1, wherein:(a) said yieldable detent means comprises means defining aplurality of cam teeth on the head of the screw member, (b) a platedisposed in the housing adjacent the screw member head, having followermeans cooperable with said cam teeth, (c) spring means disposed in thehousing and biasing the plate into engagement with the head of the screwmember, and (d) keying means disposed on the housing and connected withsaid plate, for preventing relative rotation between the plate andhousing and for providing a floating connection therebetween, so as toenable limited self-alignment of the plate to occur with respect to thescrew member head.
 7. A fastener as defined in claim 6, wherein:(a) saidkeying means comprises an end cover plate for the housing, having akeying aperture in the center thereof, (b) a shaft rigidly connectedwith the plate, and having an external surface configuration enabling itto be received in non-rotating relation in the keying aperture of theend cover plate.
 8. A fastener as defined in claim 1, and furtherincluding:(a) means defining a floating connection between the housingand the supporting structure to compensate for slight misalignmentsbetween the stud and panel, and the access opening.
 9. A fastener asdefined in claim 1, and further including:(a) a sheet metal clampingring joining the housing to the rear of the supporting surface, at theaccess opening thereof.
 10. A fastener as defined in claim 1,wherein:(a) said yieldable detent means comprises a plate member, and(b) cooperable cam teeth on said members, adapted to uni-directionallyby-pass each other.
 11. A fastener as defined in claim 1, wherein:(a)said yieldable detent means comprises a disk-like abutment member, (b)camming means on said members, providing a one-way rotary drivetherebetween, (c) the cross dimension of said disk-like member beingsufficiently less than the bore diameter to permit lateral shifting ofthe disk-like member if required, in order that the camming means on themembers can align properly with each other.
 12. A fastener as defined inclaim 1, wherein:(a) said yieldable detent means comprises a disk-likeabutment member, (b) camming means on said members, providing a one-wayrotary drive therebetween, (c) said screw member having a head, and thecross dimension of said head being sufficiently less than the borediameter so as to permit lateral shifting of the screw member ifrequired, in order that the camming means on the members can alignproperly with each other.
 13. A fastener as defined in claim 1,wherein:(a) said yieldable detent means comprises a disk-like abutmentmember, and (b) keying means between the abutment member and thehousing, permitting both limited lateral shifting of the abutmentmember, and limited axial shifting thereof in the housing.
 14. Afastener as defined in claim 1, wherein:(a) said housing has an internalannular shoulder, (b) a thrust washer disposed against said shoulder,and (c) said yieldable detent means comprising means normally biasingthe head of said screw member into engagement with said thrust washer,and also permitting limited lateral shifting of the screw member withinsaid housing bore.
 15. A fastener as defined in claim 1, wherein:(a) theyieldable detent means is disposed completely within said housing, so asto be essentially completely inaccessible from the exterior thereof,thereby being resistant to inadvertent damage and tampering.
 16. Afastener as defined in claim 1, wherein:(a) the yieldable detent meansis completely concealed by said housing, so as to be essentiallycompletely inaccessible from the exterior thereof.
 17. A fastener asdefined in claim 1, wherein:(a) said housing constitutes an enclosure tokeep debris from contact with the said yieldable detent means.
 18. Afastener as defined in claim 1, wherein:(a) said detent device and saidyieldable detent means are separate and distinct from one another.